US Patent 7954053 Extraction of datapoints from markup language documents

An extraction-rule generation and training system uses information obtained from multiple markup language documents (e.g. web pages) of similar structure to generate an extraction rule for extracting datapoints from markup language documents. Where the structures of two or more documents are not sufficiently similar, the system maintains separate extraction rules for the same datapoint, and applies these separate extraction rules in combination to particular markup language documents to extract the datapoint.